Effect of packaging materials and storage conditions on the microbial quality of pearl millet sourdough bread

Abstract

Sourdough is one of the oldest methods of cereal fermentation applied mainly for the sole purpose of baking and has been proven to enhance the production of microbiologically safe products. This study investigated the effect of packaging materials and storage conditions on the microbial quality and some intrinsic parameters of the sourdough bread. Pearl millet flour was naturally fermented for 72 h to obtain sourdough which was used with pearl millet flour to produce sourdough bread while the control bread was produced with pearl millet flour and yeast. The bread samples were packaged in low density polyethylene and aluminium foil and stored at -5, 4, 6, 28 and 37 °C. The total bacteria count (log cfu/g) and total fungal count (spore/g) increased with an increase in storage temperature and storage days. Fungi colonies isolated from stored bread samples include species of Rhizopus, Aspergillus, Penicillium and Mucor. A significant increase (p ≤ 0.05) in the pH and decrease in the moisture content of the bread samples were observed as storage period and storage temperature increased. Sourdough fermentation improved the microbial qualities and extended the shelf life of bread.

Keywords: Fermentation; Intrinsic parameters; Microbial analysis; Pearl millet; Sourdough bread.

Fig. 1

Effect of fermentation period on the physicochemical properties of pearl millet sourdough. TTA Total titratable acidity